#!/bin/bash
#
# Developed by Fred Weinhaus 11/15/2017 .......... revised 11/15/2017
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: vibrance2 [-a amount] infile outfile
# USAGE: vibrance2 [-h or -help]
#
# OPTIONS:
#
# -a     amount     vibrance amount; float>=0; default=1; no change
#
###
#
# NAME: VIBRANCE2
# 
# PURPOSE: To apply a non-linear change to the chroma channel of an image.
# 
# DESCRIPTION: VIBRANCE2 applies a non-linear change to the vibrance of an 
# image using a gamma adjustment of the chroma channel in HCL colorspace.
# 
# OPTIONS: 
# 
# -a amount ... AMOUNT is the vibrance value relative to 1. Values are floats>=0. 
# The default=1 (no change). Larger values increase the vibrance and smaller values 
# decrease the vibrance.
#
# REQUIREMENTS: IM 6.8.6-3 or greater in order to properly use HCL colorspace after a 
# bug was fixed.
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
#

# set default values
amount=1			# amount of non-linear chroma change

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}


# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 4 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		  -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-a)    # get amount
					   shift  # to get the next parameter - bluramt
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID AMOUNT SPECIFICATION ---"
					   checkMinus "$1"
					   amount=`expr "$1" : '\([.0-9]*\)'`
					   [ "$amount" = "" ] && errMsg "AMOUNT=$amount MUST BE A NON-NEGATIVE FLOAT"
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get infile and outfile
	infile="$1"
	outfile="$2"
fi

# test that infile provided
[ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED"

# test that outfile provided
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"

tmp1A="$dir/vibrance_1_$$.mpc"
tmp1B="$dir/vibrance_1_$$.cache"
trap "rm -f $tmp1A $tmp1B;" 0
trap "rm -f $tmp1A $tmp1B; exit 1" 1 2 3 15
#trap "rm -f $tmp1A $tmp1B; exit 1" ERR

# test input image
convert -quiet "$infile" +repage $tmp1A ||
	errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# process image
convert $tmp1A \
	-colorspace HCL -separate \( -clone 1 -gamma $amount \) \
	-swap 1,-1 +delete -set colorspace HCL -combine -colorspace sRGB \
	"$outfile"

exit 0
